Natural elements:

Grass.
Bushes.
Poplars.
Madera.
Crust.
Nits.
Landa.
Natural stone.
Water.
Air.
Earth.
Leaves.
Flores.
Trunks.
Oxygen.

Artificial elements:

Metal.
Hierro.
Painting.
Aluminum.
Goma.
Swings.
Paving.
Grava.
Cristal.
Tela.
Paper.
Artificial stone.
Lights.
Plastic.
Bricks.